title: New approaches to the biology of stomatal guard cells.
abstract: CO2 acts as an environmental signal that regulates stomatal movements. High CO2 concentrations reduce stomatal aperture, whereas low concentrations trigger stomatal opening. In contrast to our advanced understanding of light and drought stress responses in guard cells, the molecular mechanisms underlying stomatal CO2 sensing and signaling are largely unknown. Leaf temperature provides a convenient indicator of transpiration, and can be used to detect mutants with altered stomatal control. To identify genes that function in CO2 responses in guard cells, CO2-insensitive mutants were isolated through high-throughput leaf thermal imaging. The isolated mutants are categorized into three groups according to their phenotypes: (i) impaired in stomatal opening under low CO2 concentrations; (ii) impaired in stomatal closing under high CO2 concentrations; and (iii) impaired in stomatal development. Characterization of these mutants has begun to yield insights into the mechanisms of stomatal CO2 responses. In this review, we summarize the current status of the field and discuss future prospects.
authors.affiliation: Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, 812-8581 Japan.
authors.forename: Juntaro
authors.initials: J
authors.lastname: Negi
authors.forename: Mimi
authors.initials: M
authors.lastname: Hashimoto-Sugimoto
authors.forename: Kensuke
authors.initials: K
authors.lastname: Kusumi
authors.forename: Koh
authors.initials: K
authors.lastname: Iba
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism*; D055864:Droughts; D008027:Light; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation; D010641:Phenotype; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D054046:Plant Stomata / Q000201:enzymology / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D036226:Seedlings / Q000201:enzymology / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D015398:Signal Transduction; D013696:Temperature; D013817:Thermography
chemical_list: D029681:Arabidopsis Proteins; D008565:Membrane Proteins; C528438:SLAC1 protein, Arabidopsis; D002245:Carbon Dioxide
keywords: Arabidopsis; Carbon dioxide; HT1 kinase; SLAC1 anion channel; Stomata; Thermal imaging